In the construction of a modular structural element into a framework, various means are employed to connect one load bearing structural element to another. One basic type of modular construction involves the use of threaded couplings such as elbows, t-couplings, and the like which have internal threads adapted to receive external threads on the ends of tubing members. Another type of modular construction includes the use of multi-socket connects which receive the structural framework elements in a friction fit such as found in a so-called "tinker toy" fabricating toys. Such frictional joints will not carry a substantial amount of torsional load and where this is necessary or desirable spline-type couplings may be used. Yet another type of coupling useful in modular construction is disclosed in the article entitled "Connector for Composite Tubes" NASA tech briefs, Fall 1982, p. 53. As disclosed in this reference, tubular structural members may be connected by the use of tab or web elements which may be joined in an interfitting relationship.